Possible Clues:

• ... refusing to kill in half-hearted combat
• Economic (with resources)
• Spring wedding? Band needs to be frugal
• Economical inclusion of key in opening part of an Italian composition
• Mean fight shortly taking place near boxing venue
• Toll on Belgian town, economical
• Not wasteful
• Bound to keep article short
• Shape of washer attached to source of water, tight
• Economical; having mercy